Trichomoniasis vs. Chlamydia: What Are the Differences?

Trichomoniasis—often called "trich" for short—is the most common curable STD in the world. Unlike chlamydia, which is caused by bacteria, trich is caused by a microscopic protozoan parasite called Trichomonas vaginalis. The infection spreads through infected sexual fluids (pre-ejaculate, semen, and vaginal fluids) and is most commonly transmitted through vaginal sex.

Causes of trichomoniasis

The Trichomonas vaginalis parasite is the sole cause of trichomoniasis—poor hygiene, stress, or other infections cannot cause it. Trichomoniasis spreads when infected sexual fluids come into contact with the vulva, vagina, or penis. This can happen through vaginal sex, vulva-to-vulva contact, or sharing sex toys with an infected partner. The parasite primarily affects the genitals and does not typically infect the mouth, anus, or other parts of the body. Trich cannot be spread through casual contact—hugging, kissing, sharing food or drinks, or touching a toilet seat will not transmit the infection.

Symptoms of trichomoniasis

One of the reasons trich spreads so readily is that most people who have it show no symptoms at all. When symptoms do appear, they typically develop within 5 to 28 days after exposure. Trichomoniasis symptoms are much more common in people with vaginas than in people with penises.

In women, the most prominent sign of trich is vaginitis. Symptoms may include:

• Vaginal discharge that is yellow, green, or gray and has a foul odor
• Itching, burning, redness, or soreness around the vagina
• Bloody or frothy discharge
• Swelling in the genitals
• Burning or pain when urinating
• Pain or discomfort during intercourse

In men, symptoms are rare but may include penile discharge, irritation or burning inside the penis, or pain when urinating or ejaculating.

Treatment for trichomoniasis

Trich is curable with antibiotics and will not resolve on its own—leaving trichomoniasis untreated can allow the infection to persist for months and increases the risk of acquiring or transmitting HIV. Healthcare providers typically prescribe metronidazole or tinidazole, taken orally. It's important that all sexual partners are treated at the same time to prevent reinfection, and you should wait at least one week after completing treatment before having sex again.

Chlamydia is one of the most common bacterial STDs in the United States, with roughly 1.5 million cases reported each year—and many more that go undetected. It's caused by the bacteria Chlamydia trachomatis, which travels through semen, pre-ejaculate, and vaginal fluids. Because the vast majority of people with chlamydia never develop noticeable symptoms, the infection spreads easily and often without anyone knowing.

Causes of chlamydia

Chlamydia spreads through sexual contact with an infected person—it does not require ejaculation or penetration to transmit. Chlamydia can spread through vaginal, anal, or oral sex, as well as through sharing sex toys. Unlike trichomoniasis, chlamydia can infect the genitals, anus, mouth, and throat, and in rare cases can reach the eyes if infected fluids contact them. It cannot be passed through casual contact such as hugging, kissing, sharing utensils, or using a public toilet.

Symptoms of chlamydia

Between 50% and 70% of people with chlamydia never experience any symptoms, which is why it's sometimes called a "silent" infection. When symptoms do appear, they typically develop one to three weeks after exposure.

In women, symptoms may include:

• Unusual vaginal discharge (yellow or cloudy, sometimes with an odor)
• Burning or pain when urinating
• Bleeding between periods or after sex
• Pelvic pain or pain during intercourse

Chlamydia symptoms in men may include:

• Clear or milky discharge from the penis
• Burning or pain when urinating
• Swelling or tenderness in the testicles

If chlamydia infects the anus or throat, it can also cause discharge, discomfort, or soreness in those areas—though it often produces no symptoms there either.

Treatment for chlamydia

Chlamydia is curable with a short course of oral antibiotics—typically doxycycline (taken over 7 days) or azithromycin (taken as a single dose). It will not resolve without treatment. The long-term effects of untreated chlamydia can be serious, including pelvic inflammatory disease (PID), infertility, and an increased risk of contracting HIV. All recent sexual partners should be tested and treated at the same time to prevent reinfection, and you should avoid sex for at least 7 days after completing treatment. Learn more about how chlamydia is treated.

The good news about both trichomoniasis and chlamydia is that they're fully curable. With the right antibiotic treatment and a short period of abstinence, most people clear either infection within one to two weeks and go on to experience no lasting health effects. The key is catching the infection early—and since both conditions are frequently asymptomatic, that means testing rather than waiting for symptoms to appear.

Because so many cases go undetected, regular STD testing is one of the most important things sexually active people can do for their health. The CDC recommends annual chlamydia screening for sexually active women under 25, and more frequent testing for anyone with multiple partners. Pairing routine testing with safe sex practices—like consistent condom use—significantly reduces your risk of both infections.

If you're unsure whether you've been exposed to trichomoniasis, chlamydia, or other common STDs, at-home testing is a convenient, confidential way to get answers. Everlywell's at-home STD test screens for five infections—chlamydia, gonorrhea, hepatitis C, syphilis, and trichomoniasis—with a single kit, so you can know your status without a clinic visit.

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